This invention relates in general to sewing machines and in particular to a new and useful device for letting out skins which includes an arrangement of transport needles for effecting the easy feeding and removal of the skins as they are operated on in a sewing procedure.
An apparatus for letting out skins is disclosed in German Pat. No. 31 13 836 (U.S. Pat. No. 4,416,125). The apparatus comprises, in order along the draw-off direction of the skin before the parting sword, two needle bars, and behind the parting sword, one needle bar. Together the needle bars movable up and down form a holding device for the skin resting on two table boards. During the letting out process, in which the skin is parted slantwise to its lateral edges, cut, and the skin portions are offset to each other and then sewn together again, the skin is held by two clamping jaws cooperating like pliers and movable relative to each other in longitudinal directions. After the sewing, the skin is seized at the outer edge of the seam by a gripping tool movable upwardly and downwardly as well as transversely to the parting sword in a horizontal plane; and, for executing the next letting out process, it is shifted on the table boards crosswise to the parting sword and hence crosswise to the same direction.
It has now been found that the skin section already let out tends to roll up because of the seams arched in rib fashion, so that there is danger that the parting sword will during its upward movement, seize the previously formed seam. This would result in irregular distances between cuts.